<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style type="text/css">
	body{
		text-align: center;
	}
	
	#head,#container,#content,#side,#foot{
		margin:20px auto 20px auto;
		padding:20px 0px 20px 0px;
		border: 1px solid red;
	}
	
	#head,#container,#foot{
		/* 相对于浏览器的百分比大小 */
		width: 80%;
	}
	
	#container{
		border:0px;
	}
	
	#content{
		float:left;
		width: 63%;
		height: 200px;
	}
	
	#side{
		float:right;
		width: 33%;
		margin-left: 10px;
		height: 100px;
	}
	
	#foot{
		clear: both;
	}
</style>
</head>
<body>
<div id="head">head</div>
<div id="container">
	<div id="content">content</div>
	<div id="side">side</div>
</div>
<div id="foot">foot</div>
</body>
</html>